At a certain time of day, every day, my clock appears to be an hour fast. At another time of day, it appears to be an hour slow. It is neither fast nor slow. What's wrong with it?
The clock in question must be an electronic clock whose LCD display on the lower left of the hour digit is broken. Thus, an 8 appears as a 9, a 6 appears as a 5.
However, at other times of the day at 10 hrs for example, the display will correspond to 1 and a 0 with its lower left quadrant missing, indicating that the hour display is indeed damaged.